Torque converters



Sept. 18, 1956 H. L. MISCH TORQUE CONVERTERS &

Filed Dec. 26, 1951 I INVEINTOR.

HERBERT MlSCH ATTORNEYS.

TORQUE CONVERTERS Herbert L. Misch, Royal Oak, Mich., assignor to Stude-This invention relates to composite metal structures and moreparticularly to an article and method of forming such article from steeland aluminum parts.

For purposes of illustration merely, this invention will be describedwith reference to its application in connection with one of the elementsof a hydraulic vane tape torque converter, it being understood, however,that the invention can be adapted for use with other devices as well.

In such fluid coupling devices, for example, the pump element of thetorque converter is usually constructed in in such form as to serve as aportion of the housing for the converter. The vanes themselves aredisposed generally radially in the housing and they are centeredapproximately axially with respect to the outer and inner edges of thehousing element. In the form of the invention here shown, theoverhanging outer and inner portions of the housing serve to enclose theturbine and other parts of the torque converter structure which partsare disposed in the space which extends from the ends of the vanes andthe flywheel of the engine to which the pump element of the converter issecured on the one hand, to the other ends of the vanes and the outputshaft of the converter on the other hand.

This forms a complicated pump element structure which includes the vanesthemselves that are of a rather complex form and contour to enable themto energize the fluid in the converter with maximum efiiciency. A

commonly used method of forming such a pump element of a converter is bycasting the vaned element and the housing integral, the material usedbeing generally aluminum, or some lightweight alloy of aluminum, toreduce the mass of the element and its rotational moment of inertia.

It is also apparent that when the unit is cast as one piece, a morecomplex molding operation is involved and that the rough castingpresents a more difficult problem when it is necessary to remove roughspots from the surfaces of the vanes and burrs from the edges of thefluid flow passages. It should be noted too that a single casting ofaluminum must be somewhat large or relatively bulky in order to providethe necessary strength and that sometimes castings are malformed to suchan extent as to be porous. It is therefore desirable to minimize thecasting operation and yet provide a way of constructing a complex shapehaving a relatively light weight yet strong and compact form.

The principal object of this invention is to provide an article ofcomplex form, such as a vaned pump or turbine element for a torqueconverter or the like, which will have cast vanes of lightweightnonferous materiaLbut which may be assembled by being welded to a steelhousing. The composite structure may thus be completed in a manner togreatly reduce the cost of the final product so as to make it much lessexpensive than similar elements generally available at present.

Another object of this invention is to provide an article such as avaned pump or turbine element of a torque con- Patented Sept. 18, 1956 2verter wherein the vanes are cast of aluminum or its alloys and theouter shell is a steel stamping, with improved means for fixedlysecuring the cast vanes to the stamping.

A more specific object of this invention is to provide a method andmeans for securing an aluminum casting to a stamped steel housingwherein the casting is mechanically locked to the stamping, the lockingmeans itself being a steel stamping that may be welded to the housing.In one embodiment thereof, the locking means may include; one or moresteel stampings inserted into grooves in the casting and having tabswhich abut on the casting, the tabs being spot-welded to the housing tohold the casting in place. In another modification, the steel lockingmeans is shaped like a hoop and has inwardly pressed projections aroundwhich the aluminum casting is poured to secure an integral mechanicallock between the hoop and casting. The hoop may then be welded to thestamped steel housing.

Another object of this invention is to provide a method of formingcomposite articles having cooperating locking means for joining togethera cast portion which is made of a non-weldable material and a stampedportion of an other material that may be welded.

In addition to the above, other objects will appear more fully in thespecification below.

The preferred form of the invention is shown in the drawings forming apart of this specification, however, it is to be understood that theinvention is not to be limited to the details of construction andarrangements of parts here shown, since the invention is capable ofother embodiments and of being practiced or carried out in various ways.Also it is to be understood that the phraseology or terminology employedherein is for the purpose of description only and not by way oflimitation.

In the drawings:

Figure 1 is a perspective view showing a composite torque converter pumpstructure embodying the principles of this invention;

Figure 2 is a quarter-sectional view of the element of a torqueconverter shown in Figure 1;

Figure 3 is a plan view partly broken away showing the periphery of thecast vaned element of Figure 1;

Figure 4 is a view taken along line 44 of Figure 2;

Figure 5 is a fragmentary section through a modified form of thisinvention;

Figure 6 is a plan view of the modified locking element shown in Figure5;

Figure 7 is a section taken along line 77 of Figure 5; and

Figure 8 is a fragmentary section through still another modification ofthe invention.

Referring now to the drawings for a detailed description of theinvention and particularly to Figures 1 and 2, the vaned pump element ofthe torque converter made in accordance with this invention is formed ofa cast aluminum or aluminum alloy element 10 and a stamped steel shell11, the latter extending around the cast aluminum portion and axiallybeyond as at 12 to house other elements of the converter such as theturbine element 13, and to provide a means for attaching the torqueconverter pump means to a flywheel or other driving means (not shown).The stamped shell 11 also extends radially inward as at 14 to cooperatewith or have a bearing contact with an output shaft (not shown), tocomplete the space within which the operating fluid for the converter isconfined.

At the extreme right of the housing as viewed in Figure 2, a flatsurface 15 is formed on the casting 10, which as hereinafter describedfunctions to assist in locating the casting in the housing 11. Betweenflat surface 15 and the inward portion 14 of the housing, a shoulder 16is provided in the housing, which acts as a centering means .housing aresubjected to the welding operation.

taking the form of an annular seat for locating the aluminum casting inthe housing.

The vanes 17 of the pump element may have any desired shape and formaximum efliciency in a torque converter, vanes 17 are not only curved,.but also vary in thickness, which shape makes it quite difficultto formthem by any operation other than by casting. Vanes 17 are held in spacedrelation radially aboutcasting by an outer shell 18 and an inner shroud19, both of which are cast integrally with vanes 17. The shell 18 isfinished so as to have a generally flat outer periphery or flange 20,and the shell also has an inner bead 21 having an inwardly facingcylindrical surface 22 formed thereon which fits snugly on shoulder 16to center casting It in stamping 11.

It is apparent from an inspection of Figures 1 and 2, that it would bedifficult to make the entire pump element as a single casting. This isparticularly true when aluminum is used, as is customary, to reduce themass and rotational inertia of the element. In this case, the increasedquantity of aluminum needed adds to the cost of the element, and alsothe cost is increased because of the required cleaning up and machiningof the casting. The very size and complexity of such a casting wouldmake the mold relatively expensive, and would greatly add to thedifliculty of cleaning up the rough portions of the casting andparticularly the working surfaces of the vanes, the shell 18, and innershroud 19. The advantages inherent in limiting the casting operation tomerely the vaned portion of the pump element are thus obvious.

In following the teaching of this invention, the aluminum vanes, andonly as much of the pump shell and shroud as are necessary to supportthe vanes, are cast together as a unit. The remainder of the pumphousing is formed of any other material which may be relativelyinexpensive and which lends itself to a stamping operation, such assteel. It is essential, however, that the vaned casting be fixedlyjoined to the stamping without piercing it whereby to minimize thepossibility of leaks forming through which the hydraulic fluid mightpass in escaping from the converter.

One form of a means which may be used for so attaching the casting tothe housing 11 is shown in Figures 1 to 4 to which reference is nowmade. In this form of the invention, the flange 20 at the periphery ofthe casting has the spaced axially disposed grooves 23 machined therein,the sides 24 of which are disposed at right angles with respect to thefloor of each of their respective grooves, as shown in Figure 4. Saidgrooves 23 are designed to cooperate with the T-shaped steel inserts 25,by receiving the tail portions 26 thereof while the cross bars 27 areadapted to be fitted snugly against flange 29 as shown in Figures 1 and2. The edges of each of the tail portions 26 are rectangularly shaped soas to closely fit into grooves 23. The T inserts 25 may be andpreferably are made as stampings, which may be further machined, ifnecessary, to provide a snug fit in grooves 23.

In making use of this form of the invention, the cast aluminum pumpelement 10 is temporarily pressed into the annular seat formed in thestamped steel shell 11, and the inserts 25 are then placed in grooves 23to form an assembly. After the inserts are all in place, the protrudingcross bars 27 of each of the T-shaped locking members are spot-welded orotherwise integrally secured to shell 11. The cast element 10 is held inthe stamping so that the flat surface abuts the rear wall thereof andthe inner cylindrical surface 22 is centered on shoulder 16 whereby thecast part is properly located in shell 11 to hold it fixed during thewelding operation. During performance of the spot welding operation,care must be exercised to press cross bars 27 against the front side offlange and it is desirable that axial pressure be exerted on the crossbars during the welding operation so that the cast portion 10 will betightly engaged against the stamped shell 11 when the juxtaposed crossbars and the It is 4 most important in the case of a torque converterthat the pump element be fixed tightly in place to avoid all rattles andother possible sources of noise in the finished product.

The number of T locking inserts needed depends upon the forces involvedand the strength of the materials used. To preserve dynamic balance, andto minimize weight, the use of a minimum number of two diametricallyopposed inserts is preferred, but any number of inserts may be providedto complete the assembly, as long as it is dynamically balanced upon thecompletion thereof.

In one welding method it is possible to weld two juxtaposed pieces ofmetal together without having both pieces contacted by the weldingelectrodes. This welding method can best be performed in connection withthe alternative designs of welding strips adapted for use in a torqueconverter element, which strips are shown in Figures 5 to 8 inclusive,to which reference is now made.

The same form of steel shell may be used and a cast aluminum vanedportion 30 is formed which is generally similar to the vaned element 10,except that its outer periphery or flange 31 is not axially grooved.Instead, a steel ring, or hoop, 32 is cast integral with the flange 31,said ring having angularly disposed tabs 33 punched inwardly at regularintervals. Ring 32 may be initially placed in the mold during thecasting of the vaned pump element 30, and the material from which thecasting is being made will flow around tabs 33 thus locking the ringmechanically to the casting as shown in Figures 5, 7 and 8.

After the completed casting 30 is removed from the mold and suitablycleaned, it may be pressed into the annular seat provided in housing 11as explained above, and the housing 11 may then be welded to ring 32 bythe aforesaid welding technique. Since tabs 33 are embedded in the castportion 30 it is not necessary, in this instance, to take any specialprecautions such as to press the pump member axially inwardly relativeto the casting during the welding operation. The composite vanedstructure should however be firmly and concentrically seated within theshell during performance of this welding operation.

A further modification of the invention is shown in Figure 8, wherein aring 34 is disclosed as being cast integral with the pump element 30.Ring 34 may be formed generally like ring 32 except that it is wider andoverhangs the periphery of flange 31 of the vaned casting as shown at36. The overhanging portion may then be welded directly to housing 11 inthe same manner as described in connection with inserts 25, or ring 32.

The composite article, formed in the manner outlined above, makes use ofa steel housing 11 which is leakproof together with a rigidly mounted,lightweight, and relatively inexpensive vaned pump element. Thepreferred form of the invention has been disclosed in connection withthe construction of a torque converter pump but it is obvious that itcan be used in fabricating many similar composite structures where thefactors of relatively light weight, strength, and compactness areimportant. In making use of this teaching the most desirable materialfor each of the several parts of the composite structure may be selectedin accordance with the optimum specifications therefor, and all of theparts may then be subsequently assembled as here taught.

It is thus to be understood that the foregoing description is merelyillustrative of a preferred embodiment of this invention and thatvarious other forms thereof may be conceived, without departing from thespirit and scope of the invention, as set forth in the following claims.

What is claimed is:

l. A composite structure such as the pump element of a torque converteror the like formed of a ring-like steel housing having an interfittingring-like vaned aluminum casting, the two metals being incompatible froma welding standpoint, said housing having an annular space formedtherein to receive said casting, said casting having axiallydisposedslots cut therein at spaced points around its outer periphery,said casting being adapted to be pressed into said annular space withits periphery in contact with said housing, a plurality of T-shapedsteel locking means one of which is adapted to be engaged in each ofsaid slots with the tail of the T in the slot and the cross of the Tabutting the periphery of said casting, said locking means beingcompatible from a Welding standpoint with said housing, the cross ofsaid T-shaped piece being positioned with respect to said casting andsaid housing to overlay a portion of said housing, and welded jointmeans between each of the said cross parts of the T-shaped pieces andsaid housing to hold said composite structure assembled.

2. A composite structure such as the pump element of a torque converteror the like formed of a ring-like steel housing having an interfittingring-like vaned aluminum casting, the two metals being incompatible froma welding standpoint, said housing having an annular space formedtherein to receive said casting, said casting being adapted to bepressed into said annular space with its periphery in contact with saidhousing, steel locking means in the form of a ring cast integral withthe outer periphery of said vaned casting, said steel ring overhangingone edge of said casting and being positioned juxtaposed said housingwhen said housing and casting are interfitted, said locking means beingcompatible from a welding standpoint with said housing, and welded jointmeans between the overhanging portion of said compatible locking meansand said housing to hold said composite structure assembled.

3. A torque converter or the like, comprising a generally annularlyshaped steel housing and an interfitted annular member, the innerportion of said housing being provided with a seating shoulder, saidinterfitted member being cast of a light weight metal incompatible withsaid steel housing from a welding standpoint, said annular interfittedmember including a plurality of blades cast integral with inner andouter shroud members, one end of said outer shroud being adapted toengage on said seating shoulder when said housing and annular membersare interfitted, locking means cooperating with the other end of saidouter shroud, said locking means engaging the shroud in a manner toprevent the annular member from having any axial or rotative movementrelative to the housing, and said locking means being formed of amaterial that is compatible from a welding standpoint with the housingand being welded to the housing to hold said annular member immobile andseated within the housing.

References Cited in the file of this patent UNITED STATES PATENTS1,338,994 Miller May 4, 1920 2,463,581 Welsh Mar. 8, 1949 2,473,185Weiss June 14, 1949 2,494,539 Bolender Jan. 17, 1950 2,613,609 BuchiOct. 14, 1952 2,653,547 Langdon Sept. 29, 1953

